Use of semiconductor lasers in geodesic interference measurements of distances

A study was made of the use of semiconductor lasers in geodesic interference measurements of distances. Prototype experiments were carried out using a pulsed semiconductor laser operating at room temperature. The interferometer arms were equalized by determining the contrast maximum of the interference pattern on gradual reduction of the coherence length of the laser light source. The results indicated that it should be possible to simplify considerably the method and increase the precision of measurements of distances compared with the procedures employed at present.